System, Device and Method For Providing Power Outage and Restoration Notification

ABSTRACT

A system, computer program product and method to provide information related to a power distribution system based on information provided by a plurality of network elements electrically connected to a plurality of power lines of the power distribution system at a plurality of locations is provided. In one embodiment, the method comprises receiving a notification from a group of network elements that have detected a voltage signature indicating an imminent power outage, determining location information of the power outage, outputting the location information of the power outage, receiving a live notification from a first network element of the group of network elements indicating a first power restoration at a location of the first network element, determining location information of the first power restoration, and outputting the location information of the first power restoration.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/022,462, filed Jan. 21, 2008; and U.S. Provisional Application No.61/022,348, filed Jan. 20, 2008; both of which are incorporated hereinby reference in their entirety for all purposes.

FIELD OF THE INVENTION

The present invention generally relates to methods and apparatus forcommunicating notifications of power grid events, and more particularlyto systems, methods and devices for communicating notificationspertaining to a power grid event, such as a power fault or imminentpower outage.

BACKGROUND OF THE INVENTION

Electrical power for consumption at residences, offices and otherstructures is delivered by a power distribution system. A powerdistribution system may include numerous sections, which transmit powerat different voltages. A section of high voltage power transmissionlines forms a power distribution grid for transmitting power from apower plant to substations near populated areas. Various medium voltage(MV) power sections are coupled to the grid via substations to servespecific regions. An MV power section includes medium voltage powerlines carrying power having a voltage in the range of 1,000V to100,000V. Low voltage (LV) power sections are coupled to the MV powerlines via distribution transformers to serve specific groups ofstructures such as homes. In the United States, the LV power linestypically carry voltages of approximately 120V phase to ground and 240Vphase to phase.

The power distribution system includes transformers, switching devices,other devices, and miles of power lines. Maintaining the system ineffective working order is imperative for the consumer and society.Maintenance is used to identify signs of potential failure and bettermanage distribution and redistribution of power to satisfy local needs.Even with such maintenance, however, faults occasionally occur, whichtypically results in a power outage thereby preventing power delivery.Power outages also may occur due to other events, such as when inclementweather conditions or falling tree branches knock down power lines. Itis desirable that the utility operator quickly identify and respond tosuch power distribution events to minimize the adverse impact to thepower distribution system and to the consumers. In particular, it isdesirable to determine what adverse power distribution event may occur(or has occurred) and the location of such an event.

Accordingly, there is a need to collect power distribution parameterdata for use in identifying adverse power distribution events. Anotherneed is to obtain sufficient data to locate and respond to the powerdistribution event. Various embodiments of the present invention maysatisfy one or more of these needs or others.

SUMMARY OF THE INVENTION

The present invention provides a system, computer program product andmethod to provide information related to a power distribution systembased on information provided by a plurality of network elementselectrically connected to a plurality of power lines of the powerdistribution system at a plurality of locations. In one embodiment, themethod comprises receiving a notification from a group of networkelements that have detected a voltage signature indicating an imminentpower outage, determining location information of the power outage,outputting the location information of the power outage, receiving alive notification from a first network element of the group of networkelements indicating a first power restoration at a location of the firstnetwork element, determining location information of the first powerrestoration, and outputting the location information of the first powerrestoration.

The invention will be better understood by reference to the followingdetailed description taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described in the detailed description thatfollows, by reference to the noted drawings by way of non-limitingillustrative embodiments of the invention, in which like referencenumerals represent similar parts throughout the drawings. As should beunderstood, however, the invention is not limited to the precisearrangements and instrumentalities shown. In the drawings:

FIG. 1 is a block diagram of an example power line communication andpower distribution parameter measurement system;

FIG. 2 is a block diagram of an example embodiment of a backhaul nodeand sensor device according to the present invention;

FIG. 3 illustrates an example implementation of an example embodiment ofa backhaul node according to the present invention;

FIG. 4 is a block diagram of an example embodiment of an access node andsensor device according to the present invention;

FIG. 5 illustrates an example implementation of an example embodiment ofan access node according to the present invention;

FIG. 6 illustrates a plurality of sensor devices located at variouspositions for collecting power line distribution parameter dataaccording to an example embodiment of the present invention;

FIG. 7 is a flow chart illustrating processes for implementing anexample embodiment of the present invention;

FIG. 8 is a block diagram portions of a power line communication andpower parameter measurement system for implementing an exampleembodiment of the present invention;

FIG. 9 illustrates a sensor device located at a power line communicationdevice and coupled to a power line according to another exampleembodiment of the present invention; and

FIG. 10 illustrates a process for determining the locations of poweroutages and power restorations according to an example embodiment of thepresent invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following description, for purposes of explanation and notlimitation, specific details are set forth, such as particular networks,communication systems, computers, terminals, devices, components,techniques, data and network protocols, power line communication systems(PLCSs), software products and systems, enterprise applications,operating systems, development interfaces, hardware, etc. in order toprovide a thorough understanding of the present invention.

However, it will be apparent to one skilled in the art that the presentinvention may be practiced in other embodiments that depart from thesespecific details. Detailed descriptions of well-known networks,communication systems, computers, terminals, devices, PLCSs, components,techniques, data and network protocols, software products and systems,operating systems, development interfaces, and hardware are omitted soas not to obscure the description of the present invention.

Following is a description of example embodiments of a power linecommunication system that includes a power line parameter measurementsystem. The PLCS may include power line parameter sensor devices,various communication devices, communication protocols, andimplementation software. Also described are exemplary networktopologies. Such systems and devices may be implemented in variousembodiments according to the present invention to detect and locate thesources of power distribution events. According to various embodiments,the power line communication devices and sensor devices may be locatedthroughout the power distribution system to obtain, process, andcommunicate power line parameter data.

As discussed, a power distribution event may comprise a power line faultor a power outage. These events sometimes may be preceded by an abnormalcurrent draw (and/or other change in parameter(s) such as a voltage dip)that may signal, for example, an imminent fault or outage. The powerline communication equipment described herein may be configured toprocess power line parameter data collected from one or more sensordevices to determine if the characteristics of the parameter indicatethe presence of an event or an imminent event and if so, to provide anotification of such an event and location data thereof.

Power Line Communication and Sensor System

The power line communication and sensor system of the present inventionmay gather power distribution parameter data from multiple points alonga power distribution network and transmit the gathered data to a utilityoperator or other processing center. For example, sensor devices may bepositioned along overhead and underground medium voltage power lines,and along (external and/or internal) low voltage power lines. Asdiscussed, the power line parameter data may be used to detect anexisting or imminent fault or power outage (imminent in that the outageor fault is likely to occur within ten seconds, more preferably withinfive seconds, and still more preferably within two seconds).

The power line communication portion of the system also may provide usercommunication services, such as high speed broadband internet access,mobile telephone communications, other broadband communications, digitaltelevision, VoIP telephone service, streaming video and audio services,and other communication services to homes, buildings and otherstructures, and to each room, office, apartment, or other unit orsub-unit of multi-unit structures. Communication services also may beprovided to mobile and stationary devices in outdoor areas such ascustomer premises yards, parks, stadiums, and also to public andsemi-public indoor areas such as subway trains, subway stations, trainstations, airports, restaurants, public and private automobiles, bodiesof water (e.g., rivers, bays, inlets, etc.), building lobbies,elevators, etc.

In some embodiments, a power line parameter sensor device, whichincludes a sensor for measuring a parameter, is installed at one or morecommunication nodes to measure power line parameters of various regions,neighborhoods and structures. The power parameter sensor device maymeasure (meant to include measure or detect) one or more electricaldistribution parameters, which may include, for example purposes only,power usage, power line voltage, power line current, detection of apower outage, detection of water in a pad mount, detection of an openpad mount, detection of a street light failure, power delivered to atransformer, power factor (e.g., the phase angle between the voltage andcurrent of a power line), power delivered to a downstream branch, powerline temperature, data of the harmonic components of a power signal,load transients, and/or load distribution. One skilled in the art willappreciate that other types of parameter data also may be measured ordetected. The data may be processed by the nearby node and/orcommunicating to a remote device (e.g., the utility operator) forprocessing.

FIG. 1 shows components of a power line communication system that may beused to also provide a power distribution parameter measurement system.The system 104 includes a plurality of communication nodes 128 whichform communication links using power lines 110, 114 and othercommunication media. Various user devices 130 and power linecommunication devices may transmit and receive data over the links tocommunicate over an IP network 126 (e.g., the Internet). Thus, thecommunicated data may include measurement data of power distributionparameters, control data and user data. Communication nodes 128 may beany of a backhaul node 132, an access node 134, or a repeater node 135.A given node 128 may serve as a backhaul node 132, access node 134,and/or repeater node 135.

A communication link may be formed between two communication nodes 128over a communication medium. Some links may be formed over MV powerlines 110 and others over LV power lines 114. Other links may begigabit-Ethernet links 152, 154 formed, for example, via a fiber opticcable. Thus, some links may be formed using a portion 101 of the powersystem infrastructure, while other links may be formed over anothercommunication media, (e.g., a coaxial cable, a T-1 line, a fiber opticcable, wirelessly (e.g., IEEE 802.11 a/b/g, 802.16, 1G, 2G, 3G, orsatellite such as WildBlue®)). The links formed by wired or wirelessmedia may occur at any point along a communication path between an enddevice and the internet (or other device).

Each communication node 128 may be formed by one or more communicationdevices. Communication nodes which communicate over a power line mediuminclude a power line communication device. Exemplary power linecommunication devices include a backhaul device 138, an access device139, and a power line repeater 135. Communication nodes 128 whichcommunicate wirelessly may include a mobile telephone cell site, a WiMAXcell site, or a wireless access point having at least a wirelesstransceiver. Communication nodes which communicate over a coaxial cablemay include a cable modem or other modem. Communication nodes whichcommunicate over a twisted pair wire may include a DSL modem or othermodem. A given communication node typically will communicate in twodirections (either full duplex or half duplex), which may be over thesame or different types of communication media. Accordingly, acommunication node 128 may include one, two or more communicationdevices.

A backhaul node 132 may serve as an interface between a power linemedium (e.g., an MV power line 110) and an upstream node 127, which maybe, for example, connected to an aggregation point 124 that may providea connection to an IP network 126 such as the internet. The system 104typically includes one or more backhaul nodes 132. Upstreamcommunications from user premises, as well as control messages frompower line communication devices may be communicated to an access node134, to a backhaul node 132, and then transmitted to an aggregationpoint 124 which is communicatively coupled to the IP network 126.Communications may traverse the IP network to a destination, such as aweb server, power line server 118, or another end user device. Thebackhaul node 132 may be coupled to the aggregation point 124 directlyor indirectly (i.e., via one or more intermediate nodes 127). Thebackhaul node 132 may communicate with its upstream device via any ofseveral alternative communication media, such as a fiber optic cable(digital or analog (e.g., Wave Division Multiplexed)), coaxial cable,WiMAX, IEEE 802.11, twisted pair and/or another wired or wireless media.Downstream communications from the IP network 126 typically arecommunicated through the aggregation point 124 to the backhaul node 132.The aggregation point 124 typically includes an Internet Protocol (IP)network data packet router and is connected to an IP network backbone,thereby providing access to an IP network 126 (i.e., can be connected toor form part of a point of presence or POP). Any available mechanism maybe used to link the aggregation point 124 to the POP or other device(e.g., fiber optic conductors, T-carrier, Synchronous Optical Network(SONET), and wireless techniques).

An access node 134 may transmit data to, and receive data from, one ormore user devices 130 or other network destinations. Other data, such aspower line parameter data (e.g., current measured by a power linecurrent sensor) may be received by an access node's power linecommunication device 139. The data typically enters the system 104 alonga communication medium coupled to the access node 134. The data isrouted through the system 104 to a backhaul node 132. Downstream data issent through the network to a user device 130. Exemplary user devices130 include a computer 130 a, LAN, a WLAN, router 130 b, Voice-over IPendpoint, game system, personal digital assistant (PDA), mobiletelephone, digital cable box, security system, alarm system (e.g., fire,smoke, carbon dioxide, security/burglar, etc.), stereo system,television, fax machine 130 c, HomePlug residential network, or otheruser device having a data interface. The system also may be used tocommunicate utility usage data from an automated gas, water, and/orelectric power meter. A user device 130 may include or be coupled to amodem to communicate with a given access node 134. Exemplary modemsinclude a power line modem 136, a wireless modem 131, a cable modem, aDSL modem or other suitable modem or transceiver for communicating withits access node 134.

A repeater node 135 may receive and re-transmit data (i.e., repeat thedata), for example, to extend the communications range of othercommunication elements. As a communication traverses the communicationnetwork 104, backhaul nodes 132 and access nodes 134 also may serve asrepeater nodes 135, (e.g., for other access nodes and other backhaulnodes 132). Repeaters may also be stand-alone devices without additionalfunctionality. Repeaters 135 may be coupled to and repeat data on MVpower lines or LV power lines (and, for the latter, be coupled to theinternal or external LV power lines).

Backhaul Device 138:

As discussed, communication nodes, such as access nodes, repeaters, andother backhaul nodes, may communicate to and from the IP network (whichmay include the Internet) via a backhaul node 132. In one exampleembodiment, a backhaul node 132 comprises a backhaul device 138. Thebackhaul device 138, for example, may transmit communications directlyto an aggregation point 124, or to a distribution point 127 which inturn transmits the data to an aggregation point 124.

FIGS. 2 and 3 show an example embodiment of a backhaul device 138 whichmay form all or part of a backhaul node 132. The backhaul device 138 mayinclude a medium voltage power line interface (MV Interface) 140, acontroller 142, an expansion port 146, and a gigabit Ethernet (gig-E)switch 148. In some embodiments the backhaul device 138 also may includea low voltage power line interface (LV interface) 144. The MV interface140 is used to communicate over the MV power lines and may include an MVpower line coupler (not shown) coupled to an MV signal conditioner,which may be coupled to an MV modem 141. The MV power line couplerprevents the medium voltage power from passing from the MV power line110 to the rest of the device's circuitry, while allowing thecommunications signal to pass between the backhaul device 138 and the MVpower line 110. The MV signal conditioner may provide amplification,filtering, frequency translation, and transient voltage protection ofdata signals communicated over the MV power lines 110. Thus, the MVsignal conditioner may be formed by a filter, amplifier, a mixer andlocal oscillator, and other circuits which provide transient voltageprotection. The MV modem 141 may demodulate, decrypt, and decode datasignals received from the MV signal conditioner and may encode, encrypt,and modulate data signals to be provided to the MV signal conditioner.

The backhaul device 138 also may include a low voltage power lineinterface (LV Interface) 144 for receiving and transmitting data over anLV power line 114. The LV interface 144 may include an LV power linecoupler (not shown) coupled to an LV signal conditioner, which may becoupled to an LV modem 143. In one embodiment the LV power line couplermay be an inductive coupler. In another embodiment the LV power linecoupler may be a conductive coupler. The LV signal conditioner mayprovide amplification, filtering, frequency translation, and transientvoltage protection of data signals communicated over the LV power lines114. Data signals received by the LV signal conditioner may be providedto the LV modem 143. Thus, data signals from the LV modem 143 aretransmitted over the LV power lines 110 through the signal conditionerand coupler. The LV signal conditioner may be formed by a filter,amplifier, a mixer and local oscillator, and other circuits whichprovide transient voltage protection. The LV modem 143 may demodulate,decrypt, and decode data signals received from the LV signal conditionerand may encode, encrypt, and modulate data signals to be provided to theLV signal conditioner.

The backhaul device 138 also may include an expansion port 146, whichmay be used to connect to a variety of devices. For example a wirelessaccess point, which may include a wireless transceiver or modem 147, maybe integral to or coupled to the backhaul device 138 via the expansionport 146. The wireless modem 147 may establish and maintain acommunication link 150. In other embodiments a communication link isestablished and maintained over an alternative communications medium(e.g., fiber optic, cable, twisted pair) using an alternativetransceiver device. In such other embodiments the expansion port 146 mayprovide an Ethernet connection allowing communications with variousdevices over optical fiber, coaxial cable or other wired medium. In suchembodiment the modem 147 may be an Ethernet transceiver (fiber orcopper) or other suitable modem may be employed (e.g., cable modem, DSLmodem). In other embodiments, the expansion port may be coupled to aWifi access point (IEEE 802.11 transceiver), WiMAX (IEEE 802.16), ormobile telephone cell site. The expansion port may be employed toestablish a communication link 150 between the backhaul device 138 anddevices at a residence, building, other structure, another fixedlocation, or between the backhaul device 138 and a mobile device.

Various sensor devices 115 also may be connected to the backhaul device138 through the expansion port 146 or via other means (e.g., a dedicatedsensor device interface not shown). Exemplary sensors that may form partof a power distribution parameter sensor device 116 and be coupled tothe backhaul device 138 may include, a current sensor, voltage sensor, alevel sensor (to determine pole tilt), a camera (e.g., for monitoringsecurity, detecting motion, monitoring children's areas, monitoring apet area), an audio input device (e.g., microphone for monitoringchildren, detecting noises), a vibration sensor, a motion sensor (e.g.,an infrared motion sensor for security), a home security system, a smokedetector, a heat detector, a carbon monoxide detector, a natural gasdetector, a thermometer, a barometer, a biohazard detector, a water ormoisture sensor, a temperature sensor, a power factor sensor, and alight sensor. The expansion port may provide direct access to the coreprocessor (which may form part of the controller 142) through a MII(Media Independent Interface), parallel, serial, or other connection.This direct processor interface may then be used to provide processingservices and control to devices connected via the expansion port therebyallowing for a more less expensive device (e.g., sensor). The powerparameter sensor device 115 may measure and/or detect one or moreparameters, which, for example, may include power usage data, power linevoltage data, power line current data, detection of a power outage,detection of a street light failure, power delivered to a transformerdata, power factor data (e.g., the phase angle between the voltage andcurrent of a power line), power delivered to a downstream branch data,data of the harmonic components of a power signal, load transients data,and/or load distribution data. In addition, the backhaul device 138 mayinclude multiple sensor devices 115 so that parameters of multiple powerlines may be measured such as a separate parameter sensor device 116 oneach of three MV power line conductors and a separate parameter sensordevice on each of two energized LV power line conductors and one on eachneutral conductor. One skilled in the art will appreciate that othertypes of utility data also may be gathered. As will be evident to thoseskilled in the art, the expansion port may be coupled to an interfacefor communicating with the interface 206 of the sensor device 116 via anon-conductive communication link.

The backhaul device 138 also may include a gigabit Ethernet (Gig-E)switch 148. Gigabit Ethernet is a term describing various technologiesfor implementing Ethernet networking at a nominal speed of one gigabitper second, as defined by the IEEE 802.3z and 802.3ab standards. Thereare a number of different physical layer standards for implementinggigabit Ethernet using optical fiber, twisted pair cable, or balancedcopper cable. In 2002, the IEEE ratified a 10 Gigabit Ethernet standardwhich provides data rates at 10 gigabits per second. The 10 gigabitEthernet standard encompasses seven different media types for LAN, MANand WAN. Accordingly the gig-E switch may be rated at 1 gigabit persecond (or greater as for a 10 gigabit Ethernet switch).

The switch 148 may be included in the same housing or co-located withthe other components of the node (e.g., mounted at or near the sameutility pole or transformer). The gig-E switch 148 maintains a table ofwhich communication devices are connected to which switch 148 port(e.g., based on MAC address). When a communication device transmits adata packet, the switch receiving the packet determines the datapacket's destination address and forwards the packet towards thedestination device rather than to every device in a given network. Thisgreatly increases the potential speed of the network because collisionsare substantially reduced or eliminated, and multiple communications mayoccur simultaneously.

The gig-E switch 148 may include an upstream port for maintaining acommunication link 152 with an upstream device (e.g., a backhaul node132, an aggregation point 124, a distribution point 127), a downstreamport for maintaining a communication link 152 with a downstream device(e.g., another backhaul node 134; an access node 134), and a local portfor maintaining a communication link 154 to a Gig-E compatible devicesuch as a mobile telephone cell cite 155 (i.e., base station), awireless device (e.g., WiMAX (IEEE 802.16) transceiver), an access node134, another backhaul node 132, or another device. In some embodimentsthe gig-E switch 148 may include additional ports.

In one embodiment, the link 154 may be connected to mobile telephonecell site configured to provide mobile telephone communications (digitalor analog) and use the signal set and frequency bands suitable tocommunicate with mobile phones, PDAs, and other devices configured tocommunicate over a mobile telephone network. Mobile telephone cellsites, networks and mobile telephone communications of such mobiletelephone cell sites, as used herein, are meant to include analog anddigital cellular telephone cell sites, networks and communications,respectively, including, but not limited to AMPS, 1G, 2G, 3G, GSM(Global System for Mobile communications), PCS (Personal CommunicationServices) (sometimes referred to as digital cellular networks), 1×Evolution-Data Optimized (EVDO), and other cellular telephone cell sitesand networks. One or more of these networks and cell sites may usevarious access technologies such as frequency division multiple access(FDMA), time division multiple access (TDMA), or code division multipleaccess (CDMA) (e.g., some of which may be used by 2G devices) and othersmay use CDMA2000 (based on 2G Code Division Multiple Access), WCDMA(UMTS)—Wideband Code Division Multiple Access, or TD-SCDMA (e.g., someof which may be used by 3G devices).

The gig-E switch 148 adds significant versatility to the backhaul device138. For example, several backhaul devices may be coupled in a daisychain topology (see FIG. 10), rather than by running a different fiberoptic conductor to each backhaul node 134. Additionally, the local gig-Eport allows a communication link 154 for connecting to high bandwidthdevices (e.g., WiMAX (IEEE 802.16) or other wireless devices). The localgig-E port may maintain an Ethernet connection for communicating withvarious devices over optical fiber, coaxial cable or other wired medium.Exemplary devices may include user devices 130, a mobile telephone cellcite 155, and sensor devices (as described above with regard to theexpansion port 146.

Communications may be input to the gig-E switch 148 from the MVinterface 140, LV interface 144 or expansion port 146 through thecontroller 142. Communications also may be input from each of theupstream port, local port and downstream port. The gig-E switch 148 maybe configured (by the controller 142 dynamically) to direct the inputdata from a given input port through the switch 148 to the upstreamport, local port, or downstream port. An advantage of the gig-E switch148 is that communications received at the upstream port or downstreamport need not be provided (if so desired) to the controller 142.Specifically, communications received at the upstream port or downstreamport may not be buffered or otherwise stored in the controller memory orprocessed by the controller. (Note, however, that communicationsreceived at the local port may be directed to the controller 142 forprocessing or for output over the MV interface 140, LV interface 144 orexpansion port 146). The controller 142 controls the gig-E switch 148,allowing the switch 148 to pass data upstream and downstream (e.g.according to parameters (e.g., prioritization, rate limiting, etc.)provided by the controller). In particular, data may pass directly fromthe upstream port to the downstream port without the controller 142receiving the data. Likewise, data may pass directly from the downstreamport to the upstream port without the controller 142 receiving the data.Also, data may pass directly from the upstream port to the local port ina similar manner; or from the downstream port to the local port; or fromthe local port to the upstream port or downstream port. Moving such datathrough the controller 142 would significantly slow communications orrequire an ultra fast processor in the controller 142. Data from thecontroller 142 (originating from the controller 142 or received via theMV interface 140, the LV interface 144, or expansion port 146) may besupplied to the Gig-E switch 148 for communication upstream (ordownstream) via the upstream port (or downstream port) according to theaddress of the data packet. Thus, data from the controller 142 may bemultiplexed in (and routed/switched) along with other data communicatedby the switch 148. As used herein, to route and routing is meant toinclude the functions performed by of any a router, switch, and bridge.

The backhaul device 138 also may include a controller 142 which controlsthe operation of the device 138 by executing program codes stored inmemory. In addition, the program code may be executable to process themeasured parameter data to, for example, convert the measured data tocurrent, voltage, or power factor data. The backhaul 138 may alsoinclude a router, which routes data along an appropriate path. In thisexample embodiment, the controller 142 includes program code forperforming routing (hereinafter to include switching and/or bridging).Thus, the controller 142 may maintain a table of which communicationdevices are connected to port in memory. The controller 142, of thisembodiment, matches data packets with specific messages (e.g., controlmessages) and destinations, performs traffic control functions, performsusage tracking functions, authorizing functions, throughput controlfunctions and similar related services. Communications entering thebackhaul device 138 from the MV power lines 110 at the MV interface 140are received, and then may be routed to the LV interface 144, expansionport 146 or gig-E switch 148. Communications entering the backhauldevice 138 from the LV power lines 114 at the LV interface 144 arereceived, and may then be routed to the MV interface 140, the expansionport 146, or the gig-E switch 148. Communications entering the backhauldevice 138 from the expansion port 146 are received, and may then berouted to the MV interface 140, the LV interface 144, or the gig-Eswitch 148. Accordingly, the controller 142 may receive data from the MVinterface 140, LV interface 144 or the expansion port 146, and may routethe received data to the MV interface 140, LV interface 144, theexpansion port 146, or gig-E switch 148. In this example embodiment,user data may be routed based on the destination address of the packet(e.g., the IP destination address). Not all data packets, of course, arerouted. Some packets received may not have a destination address forwhich the particular backhaul device 138 routes data packets.Additionally, some data packets may be addressed to the backhaul device138. In such case the backhaul device may process the data as a controlmessage.

Access Device 139:

The backhaul nodes 132 may communicate with user devices directly or viaone or more access nodes 134, which may include an access device 139.FIGS. 4 and 5 show an example embodiment of such an access device 139for providing communication services to mobile devices and to userdevices at a residence, building, and other locations. Although FIG. 5shows the access node 134 coupled to an overhead power line, in otherembodiments an access node 134 (and its associated sensor devices 115)may be coupled to an underground power line.

In one example embodiment, access nodes 124 provide communicationservices for user devices 130 such as security management; IP networkprotocol (IP) packet routing; data filtering; access control; servicelevel monitoring; service level management; signal processing; andmodulation/demodulation of signals transmitted over the communicationmedium.

The access device 139 of this example node 134 may comprise a bypassdevice that moves data between an MV power line 110 and an LV power line114. The access device 139 may include a medium voltage power lineinterface (MV Interface) 140 having a MV modem 141, a controller 142, alow voltage power line interface (LV interface) 144 having a LV modem143, and an expansion port 146, which may have the functionality,functional components (and for connecting to devices, such as power lineparameter sensor device 115) as previously described above with regardof the backhaul device 138. The access device 139 also may include agigabit Ethernet (gig-E) port 156. The gig-E port 156 maintains aconnection using a gigabit Ethernet protocol as described above for thegig-E switch 146 of FIG. 6. The power parameter sensor device 116 may beconnected to the access device 139 to measure and/or detect one or moreparameters of the MV power and/or the LV power line, which, for example,may include power usage data, power line voltage data, power linecurrent data, detection of a power outage, detection of a street lightfailure, power delivered to a transformer data, power factor data (e.g.,the phase angle between the voltage and current of a power line), powerdelivered to a downstream branch data, data of the harmonic componentsof a power signal, load transients data, and/or load distribution data.In addition, the access device 134 may include multiple sensor devices116 so that parameters of multiple power lines may be measured such as aseparate parameter sensor device 116 on each of three MV power lineconductors and a separate parameter sensor device on each of twoenergized LV power line conductors and one on each neutral conductor.One skilled in the art will appreciate that other types of utility dataalso may be gathered. The sensor devices 115 described herein may beco-located with the power line communication device with which thesensor device 115 communicates or may be displaced from such device(e.g., at the next utility pole or transformer).

The Gig-E port 156 may maintain an Ethernet connection for communicatingwith various devices over optical fiber, coaxial cable or other wiredmedium. For example, a communication link 157 may be maintained betweenthe access device 139 and another device through the gig-E port 156. Forexample, the gig-E port 156 may provide a connection to user devices130, sensor devices (as described above with regard to the expansionport 146, such as to power line parameter sensor device 115), or a cellstation 155.

Communications may be received at the access device 139 through the MVinterface 140, LV interface 144, expansion port 146 or gig-E port 156.Communications may enter the access device 139 from the MV power lines110 through the MV interface 140, and then may be routed to the LVinterface 142, expansion port 146 or gig-E port 156. Communications mayenter the access device 139 from the LV power lines 114 through the LVinterface 144, and then may be routed to the MV interface 140, theexpansion port 146, or the gig-E port 156. Communications may enter theaccess device 139 from the expansion port 146, and then may routed tothe MV interface 140, the LV interface 144, or the gig-E port 156.Communications may enter the access device 139 via the gig-E port 156,and then may be routed to the MV interface 140, the LV interface 144, orthe expansion port 146. The controller 142 controls communicationsthrough the access device 139. Accordingly, the access device 139receives data from the MV interface 140, LV interface 144, the expansionport 146, or the gig-E port 156 and may route the data to the MVinterface 140, LV interface 144, expansion port 146, or gig-E port 156under the direction of the controller 142. In one example embodiment,the access node 134 may be coupled to a backhaul node 132 via a wiredmedium coupled to Gig-E port 156 while in another embodiment, the accessnode is coupled to the backhaul node 132 via an MV power line (via MVinterface 140). In yet another embodiment, the access node 134 may becoupled to a backhaul node 132 via a wireless link (via expansion port146 or Gig-E port 156). In addition, the controller may include programcode that is executable to control the operation of the device 139 andto process the measured parameter data to, for example, convert themeasured data to current, voltage, or power factor data.

Other Devices:

Another communication device is a repeater (e.g., indoor, outdoor, lowvoltage (LVR) and/or medium voltage) which may form part of a repeaternode 135 (see FIG. 1). A repeater serves to extend the communicationrange of other communication elements (e.g., access devices, backhauldevices, and other nodes). The repeater may be coupled to power lines(e.g., MV power line; LV power line) and other communication media(e.g., fiber optical cable, coaxial cable, T-1 line or wireless medium).Note that in some embodiments, a repeater node 135 may also include adevice for providing communications to a user device 130 (and thus alsoserve as an access node 134).

In various embodiments a user device 130 is coupled to an access node134 using a modem. For a power line medium, a power line modem 136 isused. For a wireless medium, a wireless modem is used. For a coaxialcable, a cable modem is may be used. For a twisted pair, a DSL modem maybe used. The specific type of modem depends on the type of mediumlinking the access node 134 and user device 130.

In addition, the PLCS may include intelligent power meters, which, inaddition to measuring power usage, may include a parameter sensor device115 and also have communication capabilities (a controller coupled to amodem coupled to the LV power line) for communicating the measuredparameter data to the access node 134. Detailed descriptions of someexamples of such power meter modules are provided in U.S. patentapplication Ser. No. 11/341,646, filed on Jan. 30, 2006 entitled, “PowerLine Communications Module and Method,” which is hereby incorporatedherein by reference in it entirety.

A power line modem 136 couples a communication onto or off of an LVpower line 114. A power line modem 136 is coupled on one side to the LVpower line. On the other side, the power line modem 136 includes aconnector to connect to a wired or wireless medium leading to the userdevice 130. One protocol for communicating with access nodes 132 over anLV power line is the HomePlug 1.0 standard of the HomePlug® Alliance forrouting communications over low voltage power lines. In this manner, acustomer can connect a variety of user devices 130 to the communicationnetwork 104.

Power Distribution Parameter Sensor Device:

In an example embodiment, the sensor device may comprise a power linecurrent sensor that is formed of a Rogowski coil and such sensor devicemay be installed throughout a network (on both MV and LV power lines).The Rogowski coil is an electrical device for measuring alternatingcurrent (AC) or high speed current pulses. An exemplary embodimentincludes a first and second helical coils of wire (loops) electricallyconnected in series with each other. The first loop is wound with asubstantially constant winding density in a first direction around acore that has a substantially constant cross section. The second loop iswound with a substantially constant winding density in a seconddirection around a core that has a substantially constant cross section.A conductor (e.g., a power line) whose current is to be measuredtraverses through the loops. A voltage may be induced in the coil basedon the rate of change of the current running through the power line.Rogowski coils may have other configurations as well.

One advantage of a Rogowski coil is that it may be open-ended andflexible, allowing it to be wrapped around an energized conductor. Also,a Rogowski coil may include an air core (or other dielectric core)rather than an iron core, which gives the coil a low inductance and anability to respond to fast-changing currents. Further, the Rogowski coiltypically is highly linear, even when subjected to large currents, suchas those of low voltage and medium voltage power lines. By forming theRogowski coil with equally spaced windings, effects of electromagneticinterference may be substantially avoided and therefore the output ofthe Rogowski coil is proportional only to the current in the threadingconductor. On method of providing equal spaced windings is to useprinted circuit boards to manufacture the coil. In one embodiment, aRogowski coil that does not include reverse direction interleavedwindings may be used (and that is not formed of a printed circuitboard). Other types of current sensors also may be used as well.

A power line parameter sensor device 115 may be located in the vicinityof, and communicatively coupled to, a power line communication device134, 135, 132 (referred to herein as a power line communication device137, which is meant to refer any of such devices 134, 135, 132). Thepower line parameter sensor device 115 measures (which may includesimply detecting the presence of (or absence of) a parameter in someinstances) a power distribution parameter, such as current, voltage,power usage data, detection of a power outage, power delivered to atransformer data (i.e., wherein the sensor device is coupled theconductor that connects the distribution transformer to the MV powerline), power factor (e.g., derived from (the cosine of) the anglebetween the voltage and current of a power line), power delivered to adownstream branch, harmonic components of a power signal, loadtransients, and/or load distribution. One skilled in the art willappreciate that other types of utility parameters also may be measured.The measured parameter may be sampled by the sensor device (or powerline communication device 137) and communicated to a power line server118 (or power line communication device 137), or other power linedistribution management system and/or power line communicationmanagement system, which may process the data to determine whether thecharacteristics of the parameter match those of a triggering event(discussed below).

In various embodiments, the power line distribution parameter sensordevice 115 may measure or detect a parameter of a power line 110, 114,such as current, voltage, power usage data, detection of a power outage,detection of a street light failure, power delivered to a transformerdata (e.g., the sensor device may be coupled to (or on the side(s)) ofthe tap conductor 165 that connects the distribution transformer to theMV power line), power factor (e.g., the phase angle between the voltageand current of a power line, which may be determined by processing datafrom multiple sensors (i.e., current and voltage)), power delivered to adownstream branch data, data of the harmonic components of a powersignal, load transients data, load distribution data, and/or othercharacteristics. One skilled in the art will appreciate that other typesof parameter data also may be gathered. In addition, one sensor device115 may be configured to provide data of more than one parameter. Forexample, a sensor device 115 may be configured to provide data of thevoltage and current carried by the power line (and therefore havemultiple sensors). One or more sensor devices 115 may be installed at agiven power line 110 and/or 114 and be coupled to a corresponding powerline communication device 137. For example, a power line current sensordevice may be installed at power lines 110 and 114 alone or with anotherpower line parameter sensor device (e.g., a power line voltage sensordevice). Such a configuration may be used to determine the current andpower into and out of a transformer. In addition, the data provided bythe sensor device 115 may be used to determine additional parameters(either by the sensor device, the power line communication device, or aremote computer). For example, a sensor device 115 may be configured tomeasure the instantaneous voltage and current (e.g., over brief timeperiod). The measurement data may be provided to the power linecommunication device 137 for processing. With adequate voltage andcurrent sampling, the device 137 may compute the power factor of thepower line (through means well known in the art). Thus, other power lineparameters may be measured using an appropriate sensor device coupled toa power line 110, 114 in the vicinity of a power line communicationdevice 137 in place of, or in addition to, the power line current sensordevice.

The parameter sensor devices 115 and applications for using the relateddata also be incorporated in power line communication systems thatcommunicate over underground power lines. Detailed descriptions of thecomponents, features, and power line communication devices of someexample underground PLCS are provided in U.S. patent application Ser.No. 11/399,529 filed on Apr. 7, 2006 entitled, “Power LineCommunications Device and Method,” which is hereby incorporated hereinby reference in its entirety. The parameter sensor devices 115 describedherein (or portions thereof) may be formed in or integrated withcouplers for coupling communication signals to and from the power lines.For example, the Rogowski coils described above may be attached to thetransformer side of the coupler (or integrated into the coupler) thatcouples to the underground (or overhead) MV power lines to allowinstallation of the coupler to also accomplish installation of thesensor device 115. Detailed descriptions of the components, features,and implementations of some example sensor devices are provided in U.S.patent application Ser. No. 11/555,740 filed on Nov. 2, 2006 entitled,“Power Line Communication and Power Distribution Parameter MeasurementSystem and Method,” which is hereby incorporated herein by reference inits entirety.

Network Communication Protocols:

The communication network 104 may provide high speed internet access andother high data-rate data services to user devices, homes, buildings andother structure, and to each room, office, apartment, or other unit orsub-unit of multi-unit structure. In doing so, a communication link isformed between two communication nodes 128 over a communication medium.Some links are formed by using a portion 101 of the power systeminfrastructure. Specifically, some links are formed over MV power lines110, and other links are formed over LV power lines 114. Still otherlinks may be formed over another communication media, (e.g., a coaxialcable, a T-1 line, a fiber optic cable, wirelessly (e.g., IEEE 802.11a/big, 802.16, 1G, 2G, 3G, or satellite such as WildBlue®)). Some linksmay comprise wired Ethernet, multipoint microwave distribution system(MMDS) standards, DOCSIS (Data Over Cable System InterfaceSpecification) signal standards or another suitable communicationmethod. The wireless links may also use any suitable frequency band. Inone example, frequency bands are used that are selected from amongranges of licensed frequency bands (e.g., 6 GHz, 11 GHz, 18 GHz, 23 GHz,24 GHz, 28 GHz, or 38 GHz band) and unlicensed frequency bands (e.g.,900 MHz, 2.4 GHz, 5.8 GHz, 24 GHz, 38 GHz, or 60 GHz (i.e., 57-64 GHz)).

Accordingly, the communication network 104 includes links that may beformed by power lines, non-power line wired media, and wireless media.The links may occur at any point along a communication path between abackhaul node 132 and a user device 130, or between a backhaul node 132and a distribution point 127 or aggregation point 124.

Communication among nodes 128 may occur using a variety of protocols andmedia. In one example, the nodes 128 may use time division multiplexingand implement one or more layers of the 7 layer open systemsinterconnection (OSI) model. For example, at the layer 3 ‘network’level, the devices and software may implement switching and routingtechnologies, and create logical paths, known as virtual circuits, fortransmitting data from node to node. Similarly, error handling,congestion control and packet sequencing can be performed at Layer 3. Inone example embodiment, Layer 2 ‘data link’ activities include encodingand decoding data packets and handling errors of the ‘physical’ layer 1,along with flow control and frame synchronization. The configuration ofthe various communication nodes may vary. For example, the nodes coupledto power lines may include a modem that is substantially compatible withthe HomePlug 1.0 or A/V standard. In various embodiments, thecommunications among nodes may be time division multiple access orfrequency division multiple access.

Software:

The communication network 104 may be monitored and controlled via apower line server that may be remote from the structure and physicallocation of the network elements. The controller of the nodes 128describe herein may include executable program code for controlling theoperation of the nodes and responding to commands. The PLS may transmitany number of commands to a backhaul nodes 132 and access nodes 134 tomanage the system. As will be evident to those skilled in the art, mostof these commands are equally applicable for backhaul nodes 132 andaccess nodes 134. For ease of discussion, the description of thecommands will be in the context of a node 128 (meant to include both).These commands may include altering configuration information,synchronizing the time of the node 128 with that of the PLS, controllingmeasurement intervals (e.g., voltage measurements), requestingmeasurement or data statistics, requesting the status of user deviceactivations, rate shaping, and requesting reset or other system-levelcommands. Any or all of these commands may require a unique responsefrom the node 128, which may be transmitted by the node 128 and receivedand stored by the PLS. The PLS may include software to transmit acommand to any or all of the nodes (134 and 132) to schedule a voltageand/or current measurement at any particular time so that all of thenetwork elements of the PLCS take the measurement(s) at the same time.

Alerts

In addition to commands and responses, the node 128 has the ability tosend Alerts and Alarms to the PLS. Alerts typically are either warningsor informational messages transmitted to the PLS in light of eventsdetected or measured by the node 128. Alarms typically are errorconditions detected.

One example of an Alarm is an Out-of-Limit Alarm that indicates that anout-of-limit condition has been detected at the node 128, which mayindicate a power outage on the LV power line, an MV or LV voltage toohigh, an MV or LV voltage too low, a temperature measurement inside thenode 128 is too high, and/or other out-of-limit conditions. Informationof the Out-of-Limit condition, such as the type of condition (e.g., a LVvoltage measurement, a node 128 temperature), the Out-of-Limit thresholdexceeded, the time of detection, the amount (e.g., over, under, etc.)the out of limit threshold has been exceeded, is stored in the memory ofthe node 128 and transmitted with the alert or transmitted in responseto a request from the PLS.

Software Upgrade Handler

The Software Upgrade Handler software may be started by the node 128Command Processing software in response to a PLS command. Informationneeded to download the upgrade file, including for example the remotefile name and PLS IP address, may be included in the parameters passedto the Software Command Handler within the PLS command.

Upon startup, the Software Command Handler task may open a file transferprogram such as Trivial File Transfer Protocol (TFTP) to provide aconnection to the PLS and request the file. The requested file may thenbe downloaded to the node 128. For example, the PLS may transmit theupgrade through the Internet to the node 128 (and perhaps through thebackhaul node, and over the MV power line) where the upgrade may bestored in a local RAM buffer and validated (e.g., error checked) whilethe node 128 continues to operate (i.e., continues to communicatepackets). Finally, the task copies the downloaded software into a backupboot page in non-volatile memory, and transmits an Alert indicatingsuccessful installation to the PLS. The node 128 then makes thedownloaded software the primary boot page and reboots. When the devicerestarts the downloaded software will be copied to RAM and executed. Thedevice will then notify the PLS that it has rebooted via an alertindicating such. In addition, and through substantially the sameprocedure, new software code may be received by the controller forstorage in (e.g., to replace existing code) and execution at the mediaaccess control (MAC) layer of the LV modem and/or the MV modem of theaccess device or the backhaul device.

ADC Scheduler

Any of the nodes described herein may include an analog to digitalconverter (ADC) for measuring the voltage, current, and/or otherparameters of any power line 110,114. The ADC may be located within thepower line parameter sensor device 115 or within the power linecommunication device 137. The ADC Scheduler software, in conjunctionwith the real-time operating system, creates ADC scheduler tasks toperform ADC sampling according to configurable periods for each sampletype. Each sample type corresponds with an ADC channel. The ADCScheduler software creates a scheduling table in memory with entries foreach sampling channel according to default configurations or commandsreceived from the PLS. The table contains timer intervals for the nextsample for each ADC channel, which are monitored by the ADC scheduler.

ADC Measurement Software

The ADC Measurement Software, in conjunction with the real-timeoperating system, creates ADC measurement tasks that are responsible formonitoring and measuring data accessible through the ADC 330 such as thepower distribution parameter sensor devices 115 (including the currentsensor devices 115 and voltage sensor devices) described herein. Eachseparate measurable parameter may have an ADC measurement task. Each ADCmeasurement task may have configurable rates for processing, recording,and reporting for example.

An ADC measurement task may wait on a timer (set by the ADC scheduler).When the timer expires the task may retrieve all new ADC samples forthat measurement type from the sample buffer, which may be one or moresamples. The raw samples are converted into a measurement value. Themeasurement is given the timestamp of the last ADC sample used to makethe measurement. The measurement may require further processing. If themeasurement (or processed measurement) exceeds limit values, an alertcondition may be generated. Out of limit Alerts may be transmitted tothe PLS and repeated at the report rate until the measurement is backwithin limits. An out of limit recovery Alert may be generated (andtransmitted to the PLS) when the out of limit condition is cleared(i.e., the measured value falls back within limit conditions).

The measurements performed by the ADC, each of which has a correspondingADC measurement task, may include node 128 inside temperature, LV powerline voltage, LV power line temperature, MV power line temperature, LVpower line current, MV power line voltage, transformer temperature,and/or MV power line current for example. MV and LV power linemeasurements may be accomplished via the power line parameter sensordevices 115.

As discussed, the nodes may include value limits for most of thesemeasurements stored in memory with which the measured value may becompared. If a measurement is below a lower limit, or above an upperlimit (or otherwise out of an acceptable range), the node 128 maytransmit an Out-of-Limit Alert. Such alert may be received and stored bythe PLS. In some instances, one or more measured values are processed toconvert the measured value(s) to a standard or more conventional datavalue.

The LV power line voltage measurement may be used to provide variousinformation. For example, the measurement may be used to determine apower outage (and subsequently a restoration), or measure the power usedby a consumer (when current data is also available) or by all of theconsumers connected to that distribution transformer. In addition, itmay be used to determine the power quality of the LV power line bymeasuring and processing the measured values over time to providefrequency, harmonic content, and other power line qualitycharacteristics.

Notification Communications

As discussed, it is desirable to identify and locate power distributionevents that may adversely affect power delivery. Examples of powerdistribution events that may have adverse effects include potential andexisting power faults and power outages. A fault is an abnormalsituation in which power flows through (or to) an unintended location,such to ground, or to another electrical wire (e.g., another MV phaseconductor, or a neutral). A transient fault is a fault that is no longerpresent if power is disconnected for a short time. Faults in overheadpower lines are often transient. For example, a tree momentarilycontacting a power line may cause a transient fault. Similarly, if avoltage arc is created from a power line due to lightning, the arc maybe fed by distribution system power causing disruption to components ofthe power distribution system. If the power is disconnected for a shorttime, the voltage arc may disappear and after power is re-established,the power line may operate normally. A persistent fault is a fault thatdoes not disappear when power is disconnected. Faults in undergroundpower lines—such as a break in a underground power cable—are oftenpersistent and (if power were maintained) allow current to flow toground. High impedance faults are more common on overhead power lineswhen the power line breaks, in which case there is not an increase incurrent (e.g., the broken power “dances” on the pavement). It isdesirable to isolate a power fault while permitting continued operationof as much of the power distribution system as possible.

A power outage is a loss of power which may be measured as approximatelya zero current flow along a power line or zero voltage on a power line.A power outage may result from equipment failure in a power station, asubstation, a transformer, or an overload to the MV power lines (causinga fuse to blow, a switch to open, a recloser to open, etc.). A poweroutage may also be caused by damage to a power line (e.g., a break) asdiscussed above. A “brownout” is a term used to refer to a condition inwhich the voltage of a power line (e.g., a low voltage power line) isbelow a normal minimum level, as specified for the given distributionsystem, but greater than zero. Some brownouts, also referred to asvoltage reductions, are made intentionally to prevent a power outage.For example, power distribution capacity may be rotated among variousdistricts to avoid total area or regional blackouts when the power drawexceeds or approaches generation capacity.

Specific power line distribution parameters have been found to bereliable indicators for detecting and/or predicting faults and outages.One such parameter is power line voltage. Specifically, a voltage dropon both of the energized conductors of an LV power line 114 below athreshold voltage for a predetermined duration often precedes a powerfault and power outage. Detection of such a voltage drop (or other powerdistribution parameter event) is referred to herein as a trigger event.Another trigger event may include detection of a load imbalance above apredetermined amount (e.g., a percentage) on the energized conductors ofthe LV power line 114 for a predetermined duration. Still anothertrigger event may comprise detection of a voltage drop on an MV powerline 110 below a threshold voltage for a predetermined duration. Yetanother trigger event may comprise detection of a current increase on aMV power line 110 above a threshold current for a predeterminedduration. Another trigger event may include detection of a currentdecrease on an MV power line 110 below a threshold level for apredetermined duration. In addition, some of these trigger events (orothers), when detected in combination, may comprise additional triggerevents that may be representative (or a prediction) of a different powerdistribution event or the same power distribution event and may be amore reliable indicator of a future power distribution event.Accordingly, it may be desirable to obtain power line voltage and/orpower line current data to monitor the power distribution system tothereby identify one or more trigger events.

In many instances, a power fault occurs wherein the current exceeds thatpermitted by a protection device that may be a current limiting devicesuch as a fuse, circuit breaker, etc. The excessive current draw mayalso reduce the voltage for a short time until the protection device“trips.” When the current on the MV power line exceeds the currentthreshold, the current limiting device trips thereby stopping the flowof current to the power distribution system on the downstream side ofthe current limiting device, but does not affect the power distributionsystem on the upstream side of the device. Referring to FIG. 6, a MVpower line 110 with multiple transformers 112 connected thereto and apower line communication device 137 is installed at each transformer 112forming part of each subnet 170. In this example, a protection device199 (e.g., fuse, recloser, circuit breaker, etc.) is installed betweentransformers 112 connected to taps 160 b and 160 c. If an MV power linefault occurs downstream from the illustrated transformers 112 (i.e., tothe right of the protection device 199 in the figure), a momentaryreduction in voltage will often be experienced along the MV power line110 at each subnet 170 (and will be measured by the power linecommunications devices 137 at each transformer 112). After a short timeperiod, the protection device 199 will trip (open), stopping the flow ofcurrent to transformers 112 connected to taps 160 c and 160 d. Thus, thePLCDs 137 c and 137 d connected at subnets 170 c and 170 d will losepower and shut down. The PLCDs 137 a and 137 b connected at subnets 170a and 170 b will detect a voltage drop and then restoration of power toan acceptable value. The present invention uses the time delay of thetripping of the protection device 199 to store data and transmit a lastgasp notification by the devices 137 c and 137 d at subnets 170 c-d andreduces false positives (e.g., a false notification of a loss of power)by devices 137 upstream from the protection device 199 such as thedevices 137 a and 137 b at subnets 170 a-b.

In one example embodiment, the voltage of each LV energized conductor issample at 256 microsecond intervals that constitutes an approximately33.54 millisecond window (resulting in 131 samples), which is slightlymore than two 60 Hz AC power cycles. Next, the average of the 131 sampleset is computed based on the absolute measured value. Next, the averagevalue is compared to a reference value, which in this example is 78volts. In this embodiment, a triggering event occurs when the computedaverage over the time interval is less than or equal to the referencevoltage. If no triggering event occurs, another set of 131 samples istaken. The reference voltage in this example will result in a triggeringevent if one full AC power line cycle is lost, one half of an AC powerline cycle is lost, or the continuous RMS AC voltage drops below 86.7volts. More specifically, using this reference voltage and time intervalwindow, a triggering event will be caused by any of:

-   -   A. one full AC power line 60 Hz cycle is lost (goes to        approximately zero) when the power line voltage before the loss        (the reduction below the threshold) is at a maximum specified        power line voltage (120 V rms+10% or 132V rms);    -   B. one half of an AC power line 60 Hz cycle is lost (goes to        approximately zero) when the power line voltage before the loss        was at a minimum specified power line voltage (120 Vrms−15% or        102V rms); or    -   C. the RMS LV voltage dips below 86.7 volts for a predetermined        protracted time period (e.g., one, two, three or four cycles).

FIG. 7 is a flow chart of a process for detecting a power distributionparameter trigger event. FIG. 8 shows a portion of the power linecommunication and power distribution parameter measurement system 104 ofFIG. 1. At step 202 of FIG. 7, one or more power line parameters aremeasured. A power line communication device (PLCD) 137 (for example)receives the parameter data from the one or more power line parametersensor devices 115 (such as voltage, current, power factor, or othersensor devices). In various embodiments the PLCD 137 may be an accessdevice 139, a backhaul device 138 or repeater 135.

FIG. 8 shows an example implementation in which an access device 139(PLCD 137) receives parameter data (which may comprise digital data oranalog signals that, for example, are proportional to the measuredparameter) from a power distribution sensor device 115. The accessdevice 139 may be part of an access node that couples to a LV power line114 and a MV power line 110 (e.g., to allow data signals to bypass adistribution transformer).

Power distribution parameter sensors 115 may be located on the LV powerline 114 and/or the MV power line 110. For example, current sensors maybe coupled to each of the two energized conductors of the LV power line114 (and the neutral conductor). Multiple sensors may be communicativelycoupled to a PLCD 137 wirelessly or through a wired connection. In anexample embodiment, the access device 139 may obtain voltage samplesevery 256 microseconds from each of the two energized conductors of theLV power line 114. In various embodiments, the samples may or may not besynchronized to the 60 Hz power signal propagating along the powerlines.

At step 204, the parameter data is processed by the PLCD 137. In oneembodiment, the processing includes taking the average of the samplesover a window of time such as taking the average of the 131 samples overthe 33.54 milliseconds as described above. In another embodiment, dataof a moving sequence of power distribution parameter samples may beaveraged. For example, multiple samples may be gathered over apredetermined time period and averaged (referred to herein as a trailingaverage). In addition, the time period of the samples may move forwardin time (referred to herein as a moving window) to thereby provide amoving window trailing average. Using an average measurement over thetime interval, as opposed to an instantaneous measurement, may preventsome smaller transients (anomalies) from being falsely identified as atrigger event. The average value over the time period of the movingwindow may be compared to a threshold value such as for example 78 volts(step 206) to determine whether a reportable power distributionparameter event has occurred. With each sample, the moving window may beupdated, the average recalculated, and then compared with acorresponding threshold value. As another example, the measured data maybe converted to root mean square (rms) data. In yet another example,voltage and current data may be used to compute data of the power, thepower factor, the real power, the reactive power. and/or anotherparameter.

As stated at step 206 the processed data (voltage data) may be comparedwith trigger data (e.g., 78 volts) associated with one or more triggerevents to determine if the processed measurement data indicates any ofthe trigger events discussed above are present. The trigger data may bestored in the memory of the PLCD 137 and retrieved to be compared withthe processed measurement data to determine whether a trigger event hasoccurred. The trigger data may be different for each type of triggerevent. For example, in some instances the trigger data may be (1) amaximum threshold value, (2) a minimum threshold value (e.g., current,voltage, power factor, etc.), (3) a maximum threshold value (e.g.,current, voltage, power factor, etc.) and a minimum duration, (4) aminimum threshold value and a minimum duration, (5) and/or othercriteria. Thus, for those trigger events that include duration criteria,multiple samples may be taken (as discussed above with respect to themoving average).

When a trigger event is detected, at step 208 a notification (e.g., acommunication reporting the event) may be transmitted to the power lineserver 118 or other remote device for processing. In addition, in thisand the other embodiments, much of data processing and other processesmay be performed by a remote device (such as a backhaul node, PLS orutility computer system). For example, the measurement data may betransmitted to a remote computer system that processes the data (204)and then compares the data with the trigger data (206), and thentransmits the notification (208) if necessary. In addition, when atrigger event occurs, the device 137 may transmit a notification (a lastgasp) and store flag data in a non-volatile memory (e.g., a flag bit)prior to shutting down (due to lack of power). The stored data is thenretrieved when the device 137 powers up and informs the device 137 thatit was shut down as a result of a power loss. Upon retrieval of the datafrom memory at power up, the device 137 then sends a “live alert” to thepower line server or other remote computer indicating that its shut downwas a result of a power loss and that it has re-joined the network.

In one embodiment the moving window over which the samples are averagedmay have a duration of two 60 Hz cycles (i.e., 33.3 ms). In anotherembodiment, the moving window may have a duration of one 60 Hz cycle(16.67 ms). The specific length of the moving window may vary indifferent embodiments. However, when the window is too narrow (e.g., onecycle) there may be a risk of a false positive, (e.g., transient noise).When the window is too wide (e.g., four cycles), the effect of the event(e.g., the fault or outage) may prevent the PLCD 137 from reporting theevent or prevent a transmitted communication from reaching an upstreamdestination. For example, in the presence of an imminent power outage,the access device 139 will lose power because the power lines to whichthe PLCD 137 is connected lose power (e.g., because the power lines maybe physically cut or otherwise disrupted or a fault occurs tripping aswitch). Consequently, a sample window that is too long may prevent thePLCD 137 from identifying the trigger event and transmitting thenotification before the PLCD loses power.

In one embodiment, when the triggering event occurs the access device139 may include circuitry and software for determining the amount oftime remaining before the device 139 must send the notification (andafter such point in time the stored energy will be insufficient totransmit the notification). For example, knowing the capacitance used tostore the energy, the voltage when the voltage began its drop, and otherparameters (e.g., age of capacitor), the access device 139 can determinethe point in time (referred to herein as “the point of no return”) thatthe message must be sent. The access device 139 can then monitor thevoltage to determine if the voltage recovers (goes back up). If thevoltage recovers before the point of no return, the access device neednot transmit a notification but instead may transmit an alert and/ordata concerning the voltage drop. If the voltage does not recover beforethe point of no return, the notification is transmitted.

In some embodiments, the device 137 may have a battery as a back-uppower source. In another embodiment, a capacitor 211 (see FIG. 8) orother short term power storage device may be included in the device 137.For example, during normal operations, the device 137 may be poweredfrom power received from the LV power line 114. The capacitor 211 orother storage device may be charged from the received power. In theevent that the supply of power stops, the capacitor 211 may dischargeover a characteristic time period based on its capacitance value. Thedevice 137, having lost the power signal, will use the power dischargedfrom the capacitor 211 to transmit a “last gasp” notification upstream,thereby reporting of the power parameter distribution event before theenergy of the capacitor is fully consumed and the PLCD 137 ceasesoperating.

In one embodiment, when the PLCD 137 detects a trigger event at step206, the device's controller 142 may generate an interrupt, so thatcommunication of the event may occur immediately (i.e., take priorityover other processes being performed by the controller 142). Forexample, upon detecting a trigger event, the controller 142 may prepareand send two simple network management protocol (SNMP) traps to thepower line server 118 (or other remote computer system). The SNMP is oneof the protocols among the internet protocol suite. SNMP is used bynetwork management systems to monitor network-attached devices forconditions that warrant administrative attention. The SNMP traps allowan automated agent to notify a management station of significant events.In this case the PLS 118 is being notified of a power distributionparameter event. The SNMP trap may convey information to identify andlocate a power distribution event. In one embodiment, the serial numberof the source device (e.g., the access device 139) from which thecommunication originated. Such serial number may be correlated to a polenumber (and then to a location) or to a street address (e.g., byretrieving the data from a database storing such information) todetermine the location of the power outage. In another embodiment theMAC address of the source device is used. The communication also mayinclude one or more codes among a range of potential codes. For example,there may be a specific code for each reportable power distributionparameter event. A specific code may be transmitted with the SNMP trapaccording to the specific power distribution parameter event detected.The reported power distribution parameter event (e.g., trigger event)may be used by the PLS 118 to determine the identity of thecorresponding power distribution event (e.g., fault; outage, imminentoutage, etc.) and the location thereof.

In response to detection of the power distribution parameter event, thecontroller 142 also may prepare the device 137 for shutdown andrebooting. For example, information may be stored in non-volatile memoryindicating the reasons for the shutdown and reboot. The data samplesthat resulted in the power distribution parameter event and shutdownalso may be stored with such information. As part of the shutdownprocess, files may be closed and processes may be terminated even ifpower remains available. The device 137 need not “disconnect” itselffrom the power source or stop using power to shutdown as that term isused herein. After the device 137 restarts (e.g., after power issupplied), the stored information may be transmitted upstream to thepower line server 118 for a more detailed analysis of the event. Thus,in one embodiment SNMP traps are transmitted immediately and a detailedcommunication may be transmitted after power is re-supplied and thedevice 137 has rebooted.

In another embodiment, a more detailed communication is sent immediatelyupon detection of the power distribution parameter event. Suchcommunication may be sent instead of, or in addition to the SNMP traps.The detailed communication may include power distribution parameter data(measured and/or processed), results of the compare process, and a timestamp of when the parameter data was obtained and/or when the testresult was detected. The detailed communication also may include anidentification of the event, such as a specific code corresponding to aspecific event. The detailed communication also may include locationinformation for identifying the source location of the event. In variousembodiments the communication may include information useful foridentifying the type of event detected and the location of the sensordevice 115 or power line communication device (e.g., access device 139)where the event has been detected.

Under some conditions, it may not be possible to transmit acommunication in response to a detected power distribution parameterevent, (e.g., when the MV current exceeds threshold). In response tosuch an event, the PLCD 137 may continue to monitor the powerdistribution parameter, and wait until the fault condition no longerexists over (e.g., MV current drops below the threshold into the normalrange). Once the fault condition no longer exists, the PLCD 137 maytransmit the notification to report the event. In some embodiments, thePLCD 137 first may wait a predetermined time period (e.g., 1 second)after the fault passes before transmitting the communication. In someembodiments, the PLCD 137 may first determine that a communicationchannel is operational (permits reliable communications) beforetransmitting data.

The notification (e.g., the SNMP trap and/or detailed communication)sent from the PLCD 137 (e.g., access device 139) may be transmittedupstream along an MV power line 110. For example, the communication maypropagate toward a repeater 135 which repeats the communication onwardtoward a backhaul device 138. The backhaul device 138 then may transmitthe communication to an upstream node or aggregation point 124 whichcommunicates with a point of presence 212 for the internet 126 oranother IP based network. The communication then may continue via theinternet toward a power line server 118 or other processing center forthe utility. In some embodiments, the path from the detecting PLCD 137to the backhaul device 138 may be along MV power lines 110. In otherembodiments, one or more links between the initial PLCD 137 and backhauldevice 138 may be along fiber, cable or wireless media. The link betweenthe backhaul device 138 and aggregation point 124 typically is viafiber, cable or wireless media. The specific path and transmission mediamay vary according to the embodiment. In another example scenario inwhich a sensor device 115 is coupled to a backhaul device 138, and thebackhaul device detects the power distribution parameter event, thecommunication path may originate at the backhaul device 138 and betransmitted to an upstream node or to an aggregation point 124. In otherembodiments, the notification may be transmitted wirelessly via a mobiletelephone network, a paging network, a WiMAX network, an IEEE 802.11x(Wifi) network, or other wireless network.

Communications transmitted in response to a power distribution parameterevent ultimately may reach the power line server (PLS) 118 or othercomputing system. The PLS 118 may receive multiple communications frommultiple PLCDs affected by a common event in a given geographical area.The particular pattern of detected power distribution parameter eventsmay be a ‘signature’ for a specific type of power distribution event(e.g., tripping of a switch). The data (e.g., parameter data, parameterevent, location data, time of data sample, time of event detection, timeof communication, etc.) may be processed to determine when and where thepower distribution event is occurring (or will occur) (e.g., betweenwhat PLCDs 137 and/or utility poles). For example, if a first group ofPLCDs 137 (or one device) connected to a MV power line does not detect atrigger event and a second group of PLCDs 137 (or one device) downstreamand adjacent to the first group on the same MV power line do detect atrigger event, the PLS 118 or other computing device may process thenotification and associated data from the second group and (based on theabsence of notifications from the first group) determine that the eventis occurring between the first and second groups of PLCDs 137.

The signature (i.e., the electrical characteristics) for a given powerdistribution event may be a characteristic pattern of power distributionparameter events over an area affected by the power distribution event.For example, a fault may propagate over an area (e.g., down an MV powerline) and be detected as a series of power distribution parameter eventsin time sequence. A power outage may be detected by multiple PLCDs withthe first PLCD to communicate the event being the device closest to thesource of the power outage. A fault due to lightning may be detectedfirst at a point closest to the strike. The impact of the lightning maypropagate away from the strike point along multiple directions from thestrike point and result in an expanding radius of detected powerdistribution parameter events.

Each power distribution parameter event notification may be logged(stored) and processed. A power distribution parameter event may bedetected by different PLCDs in response to the same trigger data ordifferent power distribution trigger data. Different PLCDs may detectdifferent types of power distribution parameter events in response to acommon power distribution event. For example, the PLS 118 may receivesome communications that indicate that power line voltage dropped belowa threshold value, and receive other communications that indicate thatthe current has exceeded a threshold value (or dropped below a thresholdvalue). Such pattern may signify an imminent power outage for acorresponding area due to an imminent fault.

The PLS 118 may respond to a detected power distribution event to bettermanage power distribution within a region or area. For example, apattern of power distribution parameter events may signify that thesystem is becoming unstable amidst the power demands of the consumers.The PLS 118 may detect such conditions and activate an agent to respond.For example, a communication may be sent to a remote computer or personwho monitors the power distribution system to alert the person to takeappropriate action. Such person (or computer) may initiate a rollingbrownout to keep the power up or shut down a part of the network. Insome embodiments the PLS 118 may activate an automatic agent which makesan automated response to take an appropriate action, (e.g., a rollingbrownout is initiated automatically over an area determinedautomatically).

In some instances a PLCD 137 may be adversely affected by a given powerdistribution event, and be unable to transmit a notification. In suchcase, other PLCDs 137 may detect a power distribution parameter eventand still be able to transmit a notification. Thus, the physical patternof power distribution parameter events may include omissions ofcommunications from one or more PLCDs 137 (which itself may comprise atrigger event to the PLS). In some instances, an event may occurdownstream along an LV power subnet. The access device 139 for suchsubnet may detect a power distribution event even though the LV powerline 114 loses power. The access device 139 may communicate such eventupstream along the MV power line 110. In a scenario where the powerdistribution event occurs along an MV power line, PLCDs 137 downstreamof the event may detect a power distribution parameter event but beunable to provide a notification to their corresponding backhaul device138. However, PLCDs 137 upstream of the event also may detect a powerdistribution parameter event and be able to transmit a notificationupstream to the PLS 118. In some embodiments in which the PLCD 137 has awireless transceiver, a wireless communication may be sent. The wirelesstransceiver may be battery operated, or have a back-up battery powersource enabling communication in the presence of a power distributionevent.

FIG. 9 shows an alternative embodiment in which a line monitor sensor214 is included in the PLCD 137. In an exemplary embodiment the linemonitor sensor 214 may be, for example, the CS5461A power meterintegrated circuit provided commercially by Cirrus Logic. The linemonitor sensor 214 may be located at (or in the same housing as) a PLCD137 to monitor a specific power distribution parameter. In variousconfigurations the line monitor device 214 may measure instantaneouscurrent and/or, instantaneous voltage, and calculate instantaneouspower, real power, apparent power, I_(RMS) or V_(RMS). The line monitordevice 214 may be coupled to the LV power line 114 via a shunt resistor(not shown), current transformer (not shown) to measure current, or viaa resistive divider network (not shown) or potential transformer (notshown) to measure for voltage. The device 214 may have a single phase2-wire connection or a single phase 3-wire connection. The device 214may have a direct connection to the power line 114 or be isolated fromthe power line 114. Other sensor devices may also be used.

Referring to FIG. 10, when the remote computer (e.g., a power lineserver) receives the notifications from one or more PLCDs 137, it maydetermine the location of the outage and map the power outage on a mapthat is presented on a display (including streets and power linesthereon) to allow utility personnel to easily identify the location ofthe fault (and what protection device(s) may have tripped and needattention). As discussed above, upon powering up the access devices 139may access their non-volatile memory to determine if a flag bit isstored therein and if so, to transmit a live alert indicating that (1)the device is back on the network and (2) the device shut down becauseof a power outage. Upon receiving the live alert notifications the PLS118 may the determine the areas where power has been restored. Morespecifically, the PLS may map the power restoration (show areas wherepower is restored in a first color), the power outage (show areas wherepower is out in a second color), and unaffected areas (show areas wherepower was not disrupted in a third color) on a map that is presented ona display (including streets and power lines thereon) to allow utilitypersonnel to easily identify the locations of the outage and restoration(and what protection device(s) may have tripped and need attention). Itis worth noting that when a nested outage occurs, the PLS may receiverestoration notifications (live alerts) from only a subset of thedevices that transmitted a last gasp, which may indicate that multiplefaults occurred (and initial efforts to restore power did not restorethe power to all locations).

The PLCDs 137 may be used to read power usage data from one or moreautomated meters resident at one or more customer premises. Anothertrigger event may be a scenario wherein a PLCD 137 loses communicationswith a given meter for a predetermined time period (e.g., thirtyseconds), which may indicate a broken low voltage power line that causesa power outage to one or more customers. In response, the PLCD 137 maytransmit a notification identifying the one or more meters with whichthe PLCD 137 has lost communications. The PLS 118 may use the meteridentifying data to determine customer addresses for the meters (all ofwhich may be stored in a customer database) in order to determine thelocation of the power outage.

After the PLCDs 137 re-establishes communications with a meter, thePLCDs 137 may transmit a notification to the PLS 118 that includesinformation identifying the re-acquired meter(s). The PLS 118 may thendetermine the location (e.g., addresses) of the power restoration byusing the meter identifying information to retrieve the customeraddress(es). As discussed above, the power outage, power restoration,and unaffected areas may be displayed on a map and/or in a tabular form.Thus, the present invention facilitates the detection of power outage ata single customer premises.

Thus, by receiving notifications (last gasps) from one or more devices,the PLS 118 knows that a MV power line outage has occurred and byreceiving a notification from a device that communication has been lost,the PLS 118 knows that a low voltage power line outage has occurred.

The notifications and storages of data may include a date and time stampto allow the PLS 118, for example, to attribute multiple notificationsto a single power event. In addition, the threshold and signature dataused by the devices may be updated from transmissions from the PLS 118or other remote computer system, which are stored in memory of thedevice 139.

It is to be understood that the foregoing illustrative embodiments havebeen provided merely for the purpose of explanation and are in no way tobe construed as limiting of the invention. Words used herein are wordsof description and illustration, rather than words of limitation. Inaddition, the advantages and objectives described herein may not berealized by each and every embodiment practicing the present invention.Further, although the invention has been described herein with referenceto particular structure, materials and/or embodiments, the invention isnot intended to be limited to the particulars disclosed herein. Rather,the invention extends to all functionally equivalent structures, methodsand uses, such as are within the scope of the appended claims. Thoseskilled in the art, having the benefit of the teachings of thisspecification, may affect numerous modifications thereto and changes maybe made without departing from the scope and spirit of the invention.

1. A method of using a computer system to provide information related toa power distribution system based on information provided by a pluralityof network elements electrically connected to a plurality of power linesof the power distribution system at a plurality of locations,comprising: receiving one or more outage notification from a set of oneor more network elements that have detected a voltage signatureindicating an imminent power outage; determining location information ofthe power outage based on the one or more notifications; outputting thelocation information of the power outage; receiving a live notificationfrom a first network element of the set of network elements providingthe outage notification; wherein the live notification indicates a firstpower restoration at a location of the first network element;determining location information of the first power restoration based onthe live notification; and outputting the location information of thefirst power restoration.
 2. The method according to claim 1, whereinsaid outputting the location information of the power outage comprisesdisplaying the location of the power outage on a map on a display. 3.The method according to claim 2, wherein said outputting the locationinformation of the first power restoration comprises displaying thelocation of the power restoration on the map on the display.
 4. Themethod according to claim 1, wherein said outputting the locationinformation of the first power restoration comprises displaying thelocation of the power restoration on a map on a display.
 5. The methodaccording to claim 1, further comprising: receiving a live notificationfrom a plurality of network elements of the set of network elementsindicating a second power restoration; determining location informationof the second power restoration; and outputting the location informationof the second power restoration.
 6. The method according to claim 1,wherein the outage notifications indicate a power outage of a mediumvoltage power line, which is detected by the set of network elements bya reduction in a measurement of a voltage of a low voltage power linebelow a threshold voltage.
 7. The method according to claim 1, whereinthe outage notifications indicate a power outage of a low voltage powerline and wherein the set of network elements determine the power outageof the low voltage power line from a failure to communicate with atleast one automated power meter.
 8. The method according to claim 1,wherein said first power restoration is not a restoration of the entirepower outage, the method further comprising: displaying on a map one ormore areas of the power outage concurrently with one or more areas ofthe first power restoration.
 9. A computer program product comprising acomputer readable medium encoding a computer program for executing on acomputer system to provide a computer process for providing informationrelated to a power distribution system based on information provided bya plurality of network elements electrically connected to a plurality ofpower lines of the power distribution system at a plurality oflocations, the computer program comprising: a first module configured toreceive a notification from one or more network elements that havedetected an imminent power outage; a second module configured todetermine location information of the power outage; a third moduleconfigured to output location information of the power outage; a fourthmodule configured to receive a live notification from a first networkelement of the group of network elements indicating a first powerrestoration at a location of the first network element; a fifth moduleconfigured to determine location information of the first powerrestoration; and a sixth module configured to output the locationinformation of the first power restoration.
 10. The computer programproduct according to claim 9, wherein said third module is configured todisplay the location of the power outage on a map on a display.
 11. Thecomputer program product according to claim 10, wherein said sixthmodule is configured to display the location of the power restoration onthe map on the display.
 12. The computer program product according toclaim 9, wherein the notification indicates a power outage of a mediumvoltage power line which is detected by the one or more network elementsby a reduction in a measurement of a voltage of a low voltage power linebelow a threshold voltage.
 13. The computer program product according toclaim 9, wherein the outage notification indicates a power outage of alow voltage power line and wherein the one or more network elementsdetermine the power outage of the low voltage power line from a failureto communicate with at least one automated power meter.
 14. A method ofusing a computer system to provide information related to a powerdistribution system based on information provided by a plurality ofnetwork elements electrically connected to a plurality of power lines ofthe power distribution system at a plurality of locations, comprising:receiving a notification from a first network element that indicates afirst power outage of a medium voltage power line; determining locationinformation of the first power outage; outputting the locationinformation of the first power outage; receiving a notification from asecond network element that indicates a second power outage of a lowvoltage power line; determining location information of the second poweroutage; and outputting the location information of the second poweroutage.
 15. The method according to claim 14, further comprising:receiving a live notification from the first network element indicatinga first power restoration at a location of the first network element;determining location information of the first power restoration; andoutputting the location information of the first power restoration. 16.The method according to claim 15, further comprising: receiving a livenotification from the second network element indicating a second powerrestoration at the low voltage power line; determining locationinformation of the second power restoration; and outputting the locationinformation of the second power restoration.
 17. The method according toclaim 14, further comprising: receiving a live notification from thesecond network element indicating a second power restoration at the lowvoltage power line; determining location information of the second powerrestoration; and outputting the location information of the second powerrestoration.
 18. The method according to claim 14, wherein saidoutputting the location information of the second power outage comprisesoutputting the addresses of one or more power customers.
 19. The methodaccording to claim 14, wherein the first network element determines afirst power outage of a medium voltage power line by a reduction in ameasurement of a voltage of a low voltage power line below a thresholdvoltage.
 20. The method according to claim 14, wherein the secondnetwork element determines the second power outage of the low voltagepower line from a failure to communicate with at least one automatedpower meter.